Doctor blade assembly for printing equipment

ABSTRACT

An assembly for holding a doctor blade in adjustable position with respect to the printing cylinder. An air loaded clamping device locks the doctor blade firmly in operative position in its holder and when the doctor blade is to be removed, the air load can be relieved and the doctor blade and its mounting quickly and easily withdrawn in an endwise direction from the printing equipment without disturbing any of the other printing equipment. The adjustment also includes an air load device for urging the doctor blade against the cylinder with a predetermined amount of pressure; this biasing of the blade into proper engagement with the cylinder is made by the air loaded device and through an adjustable gear; the adjustable gear in turn, can be adjusted initially to make the proper preliminary adjustment of the blade relative to the printing cylinder.

United States Patent I72] Inventor George Vischulis Menomonee Falls,Wis.

[21] Appl. No. 829,991 a [22] Filed June 3. 1969 [45] Patented July 20,1971 [73] Assignec Zerand Corporation New Berlin, Wis.

[54] DOCTOR BLADE ASSEMBLY FOR PRINTI NG Primary Examiner-Robert E.Pulfrey Assistant Examiner-C. Cougenour Attorney-James E. NillesABSTRACT: An assembly for holding a doctor blade in adjustable positionwith respect to the printing cylinder. An air loaded clamping devicelocks the doctor blade finnly in operative position in its holder andwhen the doctor blade is to be removed, the air load can be relieved andthe doctor blade and its mounting quickly and easily withdrawn in anendwise direction from the printing equipment without disturbing any ofthe other printing equipment. The adjustment also includes an air loaddevice for urging the doctor blade against the cylinder with apredetermined amount of pressure; this biasing of the blade into properengagement with the cylinder is made by the air loaded device andthrough an adjustable gear; the adjustable gear in turn, can be adjustedinitially to make the proper preliminary adjustment of the bladerelative to the printing cylinder.

PATENTEI] JUL 20 new SHEET 2 BF 2 DOCTOR BLADE ASSEMBLY FOR PRINTINGEQUIPMENT BACKGROUND OF THE INVENTION The invention pertains generallyto equipment for printing on running webs and in which ink is applied tothe printing cylinders and must then be wiped off of the cylinder by adoctor blade. The invention relates to means for releasably and lockablyholding the doctor blade in operative position and also for adjustingthe doctor blade in any one of several directions so as to be able toprecisely lock the doctor blade with respect to its distance from, itsangle to, and its pressure engagement with the printing cylinder.

SUMMARY OF THE INVENTION The present invention relates to an air loadedclamping device for releasably locking the doctor blade and its holderin operative position, and which can then be released so that the doctorblade and its holder can be slid endwise out of the printing line andwithout the necessity for removing or adjusting other parts of themachine.

Another aspect of the invention relates to means for adjusting the angleof the doctor blade in respect to the cylinder. This means includes apivotal bar on which the blade and its mounting are located, a gearmeans for adjusting the pivot bar, and a pressurization device forurging the pivot bar through the adjustable gear means, into contactwith the printing cylinder and with the correct predetermined pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of adoctor blade assembly made in accordance with the present invention;

FIG. 2 is a cross-sectional view of a portion of the device shown inFIG. I, certain parts, being shown as being removed, broken away for thesake of clarity in the drawings;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is an enlarged detailed view of the releasable locking means forthe doctor blade holder as shown in FIG. 2; and

FIG. 6 is a transverse, elevational view, taken generally from the line66 in FIG. l,but showing the several shafts as pulled apart or in slidout fashion for clarity in the drawings, certain parts being removed,broken away, or in section for the sake of clarity in the drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT The doctor blade assembly A of thepresent invention can be used in various types of printing equipment andhas been shown in the present disclosure as being mounted on a frame Fof a gravure cart, which cart may beof the type shown in the copendingUS. Pat. application, Ser. No. 829,990 filed June 3, I969, and entitledRotary Printing Equipment," and which has been assigned to an assigneecommon with the present invention.

The printing cylinder C, which the doctor blade assembly services, maybe a gravure type cylinder and is also mounted on the frame F in theeonventionaland known manner. This cylinder rotates in the directionindicated by the curvilinear arrow in FIG. I. The cart frame F includesa pair of laterally spaced apart mounting brackets l and 2. The doctorblade assembly is mounted on the mounting brackets as follows.

A pair of vertically positioned slide plates 5 are rigidly connectedtogether at their upper end by a tie plate 6 and their lower ends arerigidly connected together by a shaft 60 which extends through the slideplates and holds them captive thereon by means of the nuts 6b threadedon the ends of the shaft 6a. Thus, the two laterally spaced apart slideplates 5 are rigidly connected together and can slide, in an axialdirection relative to the cylinder C, within the brackets 1 and 2. Forthis purpose, rollers 7 are mounted at the upper ends of the bracketsand on opposite sides of the slide plates and bear against the slideplates so that the slide plates and the doctor blade assembly which theycarry can be rcciprocated during the printing operation. The shaft 6a isslidably mounted on the frame by means of the pillow blocks 60 whichform part of the frame. Antifriction bearing assemblies 6d are journaledin the pillow blocks and shaft 6a is mounted in these bearings toprovide smooth reciprocatory movement. The means for reciprocating theslide plates and its associated doctor blade are not shown.

The slide plates 5 have a vertically elongated recess 8 formed in theircentral portion. It is in these recesses that a pair of slide blocks areguidingly and vertically positionable by means to be described, thusproviding for a vertical adjustment of the doctor blade assemblyrelative to the cylinder. This vertical adjustment is provided by a pairof threaded shafts I3 which are rotatable at their lower ends in theirrespective slide plate 5, and which shafts have a worm gear 14 fixedadjacent their lower ends. The two vertical shafts 13 are simultaneouslyrotated by the hand wheel 15 fixed to shaft 16, the shaft 16 in turnhaving a pair of pinions l7 fixed thereto for constant mesh with theirrespective worm gear 14 or shafts I3. The upper ends of the shafts I3are in threadable engagement with their respective slide blocks 10.Thus, rotation of the hand wheel 15 in one direction or the other causesvertical shifting of the slide blocks I0 and the doctor blade assembly Acarried thereby.

The doctor blade assembly also has an adjustment for varying itsposition toward and away from the gravure cylinder as follows. The slideframe SF of the doctor blade assembly is slidable in angularly disposedslide bloclks 20 which are fixedly held by their shafts 21 in frame SF.Shifting movement of the frame SF in the slide blocks 20 is accomplishedby the pair of spaced, rotatable, and threaded shafts 22 mounted in theslide frame SF. These shafts 22 are threadably engaged in the frame SFand each have a worm gear 23 fixed thereto. These worm gears 23 are inconstant mesh with their respective worms 24 (FIG. 6) fixed to atransverse shaft 25. The transverse shaft is rotatably mounted in abracket 28 and it has a hand wheel 26 fixed at its outer end. Thus,rotation of the hand wheel causes simultaneous rotation of both of thethreaded shafts 22 and consequent movement of the frame SF and itsdoctor blade assembly A in either direction toward or away from thegravure cylinder C.

Means are also provided for skewing the doctor blade relative to thecylinder, that is to say, for moving one end of the blade closer to thecylinder, while the other end is moved away from the cylinder. This isaccomplished by turning the spoken handwheel 27 (FIGS. 1 and 6), whichis in threaded engagement with the elongated bracket 28. The gears 23are mounted on this bracket so when the latter is shifted slightly, thethreaded shafts 22 which are of opposite thread, rotate slightly, thusskewing the blade.

Referring in particular to FIG. 2, the slide frame SF of the assemblyhas a pivot bar 30 pivoted at 31 and a worm gear segment 32 is fixedwith the bar 30 at a transversely central disposed location thereon. Ashaft 33 is: rotatably mounted in the frame SF and has a worm gear 34:fixed thereto for constant mesh with a worm 35. Worm 35 is fixed toshaft 36 which in turn is rotatably mounted in a sliding block 10. Handwheel 37 (FIG. 6) is connected through pinions 37a and 37b (FIGS. 3 and6) to the end of shaft 36 and can be turned in either direction toconsequently rotate its gear and also shaft 33 of the doctor bladeassembly in one direction or another. Also fixed to shaft 33 is a wormgear 38 and this worm gear 38 is in constant engagement with worm gearsegment 32 of the pivot bar. Thus, the arcuate position of the doctorblade can be varied by rotation of the hand wheel 37'. A pair of springs40 (FIG. 2) are fixed at one end as at 41 to the frame SF, and aremounted at their other ends to the pivot yoke 43. These springs act tourge the doctor blade assembly away from the gravure engaging positionand their function is to take up the backlash between the gear segment32 and the worm 38.

As shown in FIGS. 2 and 5, the doctor blade 50 is rigidly clamped in aholder 51 by means of cap screws 52. The holder has a dove tailed shapedrecess 53 formed along its lower side and by means of which it isslideably mounted on the complementary guideway 55 which extends fromthe upper side of the pivot bar.

The guideway 55 is actually comprised of two parts; 550 which is formedas an integral part of the pivot bar and 55b which is a separateguidebar and is located adjacent the wall 56 of the pivot bar. Theguidebar 55b has a recess 57 and it is in this recess that theexpansible, flexible belt 60 is located. The belt 60 is held at one endand its other end adapted to receive fluid pressure. The belt gearsagainst the wall 56 and also the guidebar so that when it ispressurized, the guidebar is forced away from the wall 56, thus actingto tightly clamp the two piece extending guideway 55 into rigidengagement with the dove tailed recess 53 of the holder.

To assemble the holder and the doctor blade in the pivot bar, theexpansible belt 60 is not pressurized and the holder can be easily slidin an endwise direction over the two piece guide 55. When it is inposition, the flexible, hollow belt 60 is pressurized, thus forcing thetwo piece guide 55 apart and locking the holder on the pivot bar.

The entire pivot bar, its holder 51 and the doctor blade 50 can bepivoted about point 31 by means other than the gear segment 32 and worm38. This additional means takes the form of an expansible air actuator70 which is fixed at the end of shaft 33. A source of fluid pressure,such as air, is introduced into the air actuator by means of the conduit72 on which it is mounted at its other side. When the air actuator ispressurized, is expands, thus forcing the shaft 33 and its gear 38 in anupward direction as viewed in FIG. 2, thus causing a thrust on gearsegment 32 and the pivot bar to which it is fixed. The amount ofpressure in the air actuator can be varied so as to in turn, vary theamount of twisting or pivoting force applied to the pivot bar and itsdoctor blade. This amount is predetermined so that the doctor blade isalways applied with the same amount of pressure to the gravure cylinder.

RESUME The present invention provides a quickly releasable and tightlylockable mounting for the doctor blade holder. The holder and its doctorblade can thereby be axially withdrawn, in a transverse direction inrespect to the printing equipment, and without disturbing and part ofthe machine. The doctor; blade and its holder can then be readilyassembled simply by sliding it endwise into the press and is quicklylocked in place by introducing fluid pressure into the expandable belt60. The doctor blade can also be quickly and accurately adjusted as tothe amount of pressure on the gravure cylinder and this adjustment ismade by the air actuator acting through the gear adjustment 32 and 38.The gear adjustment may be considered to the preliminary adjustment forinitially adjusting the angular blade relative to the cylinder and theair actuator is the final and more sensitive means for adjustment of thedoctor blade.

lclaim:

l. A mounting for adjusting a doctor blade relative to a printingcylinder and comprising, a support frame, a rotatable shaft mounted insaid frame for axial shifting in said frame, a pivot bar along saidframe and pivotally mounted thereto; gear means connected to and betweensaid frame and said pivot bar for adjusting the pivotal position of saidbar, said gear means including a worm gear segment fixed to said pivotbar, and a helical gear fixed to said rotatable shaft and in constantmesh with said worm gear segment; a doctor blade mounted on said pivotbar, and an expansible fluid actuator connected to said shaft foraxiaily shifting said shaft and also connected to said gear means forshifting said gear means and thereby pivoting said bar and blade.

2. The arrangement set forth in claim 1 including an adjustable meansfor rotating said shaft and thereby causing pivotal movement of said barand said doctor blade.

3. The arrangement set forth in claim 1 including spring means betweensaid frame and said pivot bar for eliminating backlash between said wormgear and said worm gear segment.

4. ln rotary printing equipment, a printing cylinder, a support frameextending along the length of said cylinder, a rotatable shaft mountedin said frame and axially shiftably therein, a pivot bar extending alongsaid frame and adjacent said cylinder and pivotally mounted to saidframe, gear means between said frame and said pivot bar for adjustingthe pivotal position of said bar with respect to said cylinder, saidgear means including a worm gear segment fixed to said pivot bar and ahelical gear fixed to said shaft and in constant mesh with said wormgear segment, a doctor blade mounted on said pivot bar for engagementwith said cylinder, and an expansible fluid actuator connected to saidgear means for shifting the latter and consequently shifting said pivotbar to thereby urge said doctor blade through said gear means intoengagement with said cylinder with the pressure determined by the amountof pressurization of said actuator.

5. The arrangement set forth in claim 4 including spring means betweensaid frame and said pivot bar for eliminating backlash between said wormgear and said worm gear segment.

6. The arrangement set forth in claim 4 including means for bodily andreciprocably shifting said bar and doctor blade toward and away fromsaid cylinder.

7. ln rotary printing equipment, a gravure cylinder, a support frameextending along the length of said cylinder, a shaft mounted in saidframe for rotation and axial shifting therein, a pivot bar extendingalong said frame and adjacent said cylinder and pivotally mounted tosaid frame, gear means between said frame and said pivot bar foradjusting the pivotal position of said bar with respect to saidcylinder, said gear means including a worm gear segment fixed to saidpivot bar, and a helical gear fixed to said shaft and in constant meshwith said worm gear, and an expansible fluid actuator connected to saidshaft and to said gear means for shifting the latter and consequentlypivoting said pivot bar; an elongated doctor blade holder having aguideway recess along one side thereof, said pivot bat having a guideextension along one side thereof which is complementary to andengageable by said guide recess of said holder whereby said holder canbe slid axially along said extension and be held thereby, said extensionbeing formed as two parts which are relatively separable from oneanother, and an expansible belt means between said two parts andpressurizable so as to force said parts apart and into bindingengagement with said holder recess whereby, when said belt ispressurized said holder is rigidly held on said bar, and when said beltis not pressurized said two parts release said holder so that it can bewithdrawn axially from said bar.

1. A mounting for adjusting a doctor blade relative to a printingcylinder and comprising, a support frame, a rotatable shaft mounted insaid frame for axial shifting in said frame, a pivot bar along saidframe and pivotally mounted thereto; gear means connected to and betweensaid frame and said pivot bar for adjusting the pivotal position of saidbar, said gear means including a worm gear segment fixed to said pivotbar, and a helical gear fixed to said rotatable shaft and in constantmesh with said worm gear segment; a doctor blade mounted on said pivotbar, and an expansible fluid actuator connected to said shaft foraxially shifting said shaft and also connected to said gear means forshifting said gear means and thereby pivoting said bar and blade.
 2. Thearrangement set forth in claim 1 including an adjustable means forrotating said shaft and thereby causing pivotal movement of said bar andsaid doctor blade.
 3. The arrangement set forth in claim 1 includingspring means between said frame and said pivot bar for eliminatingbacklash between said worm gear and said worm gear segment.
 4. In rotaryprinting equipment, a printing cylinder, a support frame extending alongthe length of said cylinder, a rotatable shaft mounted in said frame andaxially shiftably therein, a pivot bar extending along said frame andadjacent said cylinder and pivotally mounted to said frame, gear meansbetween said frame and said pivot bar for adjusting the pivotal positionof said bar with respect to said cylinder, said gear means including aworm gear segment fixed to said pivot bar and a helical gear fixed tosaid shaft and in constant mesh with said worm gear segment, a doctorblade mounted on said pivot bar for engagement with said cylinder, andan expansible fluid actuator connected to said gear means for shiftingthe latter and consequently shifting said pivot bar to thereby urge saiddoctor blade through said gear means into engagement with said cylinderwith the pressure determined by the amount of pressurization of saidactuator.
 5. The arrangement set forth in claim 4 including spring meansbetween said frame and said pivot bar for eliminating backlash betweensaid worm gear and said worm gear segment.
 6. The arrangement set forthin claim 4 including means for bodily and reciprocably shifting said barand doctor blade toward and away from said cylinder.
 7. In rotaryprinting equipment, a gravure cylinder, a support frame extending alongthe length of said cylinder, a shaft mounted in said frame for rotationand axial shifting therein, a pivot bar extending along said frame andadjacent said cylinder and pivotally mounted to said frame, gear meansbetween said frame and said pivot bar for adjusting the pivotal positionof said bar with respect to said cylinder, said gear means including aworm gear segment fixed to said pivot bar, and a helical gear fixed tosaid shaft and in constant mesh with said worm gear, and an expansiblefluid actuator connected to said shaft and to said gear means forshifting the latter and consequently pivoting said pivot bar; anelongated doctor blade holDer having a guideway recess along one sidethereof, said pivot bat having a guide extension along one side thereofwhich is complementary to and engageable by said guide recess of saidholder whereby said holder can be slid axially along said extension andbe held thereby, said extension being formed as two parts which arerelatively separable from one another, and an expansible belt meansbetween said two parts and pressurizable so as to force said parts apartand into binding engagement with said holder recess whereby, when saidbelt is pressurized said holder is rigidly held on said bar, and whensaid belt is not pressurized said two parts release said holder so thatit can be withdrawn axially from said bar.